<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="assets/css/amazeui.min.css">
    <style>
        *{
            margin:0;
            padding: 0;
            border: 0;
        }
        body{
            width:100%;
        }
        nav{
            width: 100%;
            position: fixed;
            bottom:0;
            left:0;
            right: 0;
            background: #00642D;
            max-height: 120px;
        }
    </style>
</head>
<body>


<nav>

</nav>


<script src="assets/js/jquery.min.js"></script>
<script src="assets/js/amazeui.min.js"></script>
<script>
    $(document).ready(function () {
        $('nav').css('height',innerWidth/5);
    })
</script>
</body>
</html>